US5672771A - Integrated process for the production of ter-amyl alkyl ethers - Google Patents

Integrated process for the production of ter-amyl alkyl ethers Download PDF

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US5672771A
US5672771A US08/546,989 US54698995A US5672771A US 5672771 A US5672771 A US 5672771A US 54698995 A US54698995 A US 54698995A US 5672771 A US5672771 A US 5672771A
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hydrocarbon stream
pentenes
ter
process according
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Roberto Trotta
Gianni Donati
Renato Paludetto
Paolo Chiudaroli
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SnamProgetti SpA
Enichem SpA
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Enichem SpA
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Assigned to SNAMPROGETTI S.P.A., ENICHEM S.P.A reassignment SNAMPROGETTI S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CHIUDAROLI, PAULO, DONATI, GIANNI, PALUDETTO, RENATO, TROTTA, ROBERTO
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01—Preparation of ethers
    • C07C41/34—Separation; Purification; Stabilisation; Use of additives
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01—Preparation of ethers
    • C07C41/05—Preparation of ethers by addition of compounds to unsaturated compounds
    • C07C41/06—Preparation of ethers by addition of compounds to unsaturated compounds by addition of organic compounds only
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01—Preparation of ethers
    • C07C41/34—Separation; Purification; Stabilisation; Use of additives
    • C07C41/36—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/12—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
    • C07C7/13—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers by molecular-sieve technique
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the present invention relates to an integrated process for the production of ter-amyl alkyl ethers.
  • the present invention relates to an integrated process for the production of ter-amyl methyl ether (TAME) or ter-amyl ethyl ether (TAEE).
  • TAME ter-amyl methyl ether
  • TEE ter-amyl ethyl ether
  • the present invention relates to the maximization of the use of the pentene fraction in an integrated cycle for the production of TAME or TAEE.
  • ter-amyl alkyl ethers consisting in reacting 2-methyl-1-butene or 2-methyl-2-butene (reactive isoamylenes), contained in C 5 hydrocarbon streams of different origins, in particular in streams coming from steam cracking or catalytic cracking plants, with an alcohol, preferably selected from methanol and ethanol.
  • an alcohol preferably selected from methanol and ethanol.
  • U.S. Pat. No. 3,979,461 describes a process for the preparation of TAME wherein the isoamylenes, contained in C 5 streams are reacted with methanol in the presence of an acid ion-exchange resin.
  • the Applicants have found a process for the production of ter-amyl alkyl ethers in connection with a cycle for the best use of the residual components still present in the C 5 stream leaving the etherification reactor.
  • the C 5 stream after synthesis and separation from the teramyl ether, is sent to an isomerization unit, for conversion of the pentene-1, pentenes-2, cis and trans, and 3-methyl-1-butene to reactive isoamylenes, and is recycled to the synthesis section of the ter-amyl alkyl ether.
  • inert products basically consisting of saturated hydrocarbons such as n-pentane and isopentane
  • a separation section with molecular sieves has been inserted between the etherification and isomerization sections for the separation of the pentanes from the pentenes and recovery of the pentenes. More specifically, the separation is obtained by means of a selective absorption of the olefins on zeolites.
  • the olefins thus absorbed can be recovered by desorption and recycled to the isomerization section. This result, however, can be obtained if the separation on molecular sieves is carried out with the stream in the vapour phase, as operating in a liquid phase produces unsatisfactory results.
  • the present invention therefore relates to an integrated process for the production of ter-amyl alkyl ethers which comprises:
  • step (c) sending the hydrocarbon stream containing the recovered pentenes, together with the possible non-fed fraction in step (c), to a skeleton isomerization section for the transformation of the linear pentenes to reactive isoamylenes;
  • the charged C 5 hydrocarbon stream can have a low content of reactive isoamylenes, if this comes, for example, from a plant for the synthesis of pre-existing ter-amyl alkyl ethers.
  • the C 5 stream can be fed directly to the isomerization section and then to the etherification section. After separation of the ether produced, the outlet stream is sent for separation of the saturated hydrocarbons, recycling the released pentene fraction to the isomerization section.
  • a further integrated process for the production of ter-amyl alkyl ethers can comprise:
  • step (c) sending the isomerized hydrocarbon stream leaving step (c), in a vapour phase, or a fraction thereof, to a molecular sieve separation section for the separation of the pentanes from the pentenes and the recovery of the pentenes;
  • step (e) recycling the isomerized stream, containing the recovered pentenes, together with the possible fraction not fed in step (d), to the synthesis reactor of the ter-amyl alkyl ether after mixing with the C 5 hydrocarbon stream to be charged.
  • the C 5 hydrocarbon stream to be charged can have a low content of reactive isoamylenes as it comes from a plant for the synthesis of pre-existing ter-amyl alkyl ethers.
  • the C 5 stream can be fed directly to the isomerization section, and then, to the molecular sieve separation section.
  • the C 5 hydrocarbon stream which is used in the process of the present invention basically consists of isopentane, isoamylenes, n-pentane, pentene-1, pentene-2, trans or cis, and, possibly, C 4 or C 6 hydrocarbons and is substantially free of isoprene and cyclopentadiene as it comes from a hydrogenation unit of these.
  • a C 5 stream in addition to a quantity of C 4 and C 6 of between, for example, 0 and 20% by weight, can comprise about: 1-70% by weight of isopentane; 0.5-30% by weight of n-pentane; 0.1-30% by weight of cyclopentane; 0.5-20% by weight of linear pentenes, taken individually; 0.1-30% by weight of cyclopentene; 0.1-10% by weight of 3-methyl-1-butene; 0.5-30% by weight of, 2-methyl-1-butene; 0.5-50% by weight of 2-methyl-2-butene; 0-2% by weight for each diolefin taken individually.
  • Any aliphatic alcohol can be used in the process of the present invention even if methyl and ethyl alcohol are preferred to produce ter-amyl methyl ether (TAME) and ter-amyl ethyl ether (TAEE) respectively.
  • TAME ter-amyl methyl ether
  • TEE ter-amyl ethyl ether
  • the etherification reaction is carried out, preferably, in a liquid phase in the presence of an acid catalyst under the traditional operating conditions.
  • the ether can be synthesized by means of a column-reactor, according to the catalytic distillation principle described, for example, in U.S. Pat. No. 4,475,005 or in European patent application 470.655.
  • the hydrocarbon stream, coming from the etherification unit, is sent to a separation section to recover the ether produced and the possible non-reacted alcohol.
  • the separation of the residual C 5 fraction from the ether is carried out in a normal distillation column from whose bottom a product is separated consisting of ether and possible C 6 + hydrocarbons. At the top of the column the C 5 hydrocarbons are recovered with the non-reacted alcohol.
  • the alcohol is then removed with the known methods, for example by extraction with water.
  • the residual C 5 fraction, without ether and alcohol, or a fraction of more than 5% by weight of the total stream available, is sent to a molecular sieve separation section to eliminate the inert products, consisting of aliphatic hydrocarbons, basically n-pentane and isopentane.
  • any molecular sieve of the zeolitic type capable of having selectivity with respect to the double olefinic bond can be used in the process of the present invention.
  • compounds can be used corresponding to those having the general formula (I):
  • Cat represents a cation of valence "n”, inter-changeable with calcium (Ca), such as sodium, lithium, potassium, magnesium, etc;
  • x is a number between 0.7 and 1.5;
  • Me represents boron or aluminium
  • y is a number between 0.8 and 200, preferably between 1.3 and 4.
  • Zeolites of the X and Y type are preferred with a particle size of between 0.1 and 3 mm. These zeolites allow selectivity ratios olefins/paraffins to be obtained of between 3 and 12, the selectivity being defined as: ##EQU1## wherein ⁇ o and ⁇ p are the adsorbed molar quantities of olefins (o) and paraffins (p) in equilibrium with the respective partial pressures P o and P p in the vapour.
  • the separation (adsorption) of the aliphatic hydrocarbons is carried out in the vapour phase at a temperature of between 20° and 180° C., preferably between 50° and 140° C., and a pressure of between 1 and 10 absolute bars, preferably between 1 and 5.
  • a system of at least two sections arranged parallel to each other so that when one section is in the adsorption phase, the other is in the desorption phase.
  • the latter is carried out by elution of the olefins adsorbed on the molecular sieves with a desorbing agent having a boiling point higher than that of the hydrocarbons treated, for example with aliphatic hydrocarbons such as hexane, heptane, octane, etc., in the vapour phase and subsequent rectification of the mixture obtained to recover the olefins.
  • a desorbing agent having a boiling point higher than that of the hydrocarbons treated, for example with aliphatic hydrocarbons such as hexane, heptane, octane, etc.
  • the process of the present invention enables the production of an aliphatic hydrocarbon stream which is practically without olefins or with a content of olefins of up to 5% by weight.
  • the olefinic stream which leaves the molecular sieve separation section basically consisting of the fraction of residual pentanes, pentene-1 and pentene-2, cis and trans, and 3-methyl-1-butene, is sent to the isomerization section for the conversion of the pentene-1 and pentene-2, cis and trans, and 3-methyl-1-butene to reactive isoamylenes.
  • the isomerization reaction can be carried out, for example, by the process described in U.S. Pat. No. 4,038,337 using, as catalyst, a product based on silicized alimina described in U.S. Pat. Nos. 4,013,589 and 4,013,590 or using zeolitic catalyts such as those, for example, described in European patent applications publications 523.838 and 501.577.
  • FIGS. 1 and 2 represent two exemplifying but not limiting forms of the embodiment
  • FIG. 3 represents an illustrative form of the single molecular sieve separation section.
  • A, B and C represent respectively the synthesis section of ter-amyl alkyl ether, the molecular sieve separation section of the aliphatic hydrocarbons and the skeleton isomerization section.
  • the feeding stream consisting of the sum of the C 5 hydrocarbon fraction (1) and the recycled fraction (11) coming from the isomerization unit C, is sent to the synthesis section A, together with the aliphatic alcohol (2).
  • the ether produced (12) has been recovered, by means of conventional systems not shown in the figure, the residual fraction (3) is sent, either totally or partially, to the separation section B. If there is a partial separation, part of the above residual fraction by-passes the separation section B (5).
  • the separation section B is located after the isomerization section C.
  • the separation section B comprises an adsorption/desorption unit D and two distillation columns E and F (FIG. 3).
  • the stream D1 practically without olefins is recovered from the adsorption phase and is sent to the distillation column E to recover the desorbent E2, to be recycled, from the discharged pentane fraction E1.
  • the olefinic fraction D2 is recovered in the desorption phase and sent to the distillation column F to recover the pentene fraction F1, to be re-admitted into the cycle, from the desorbent F2 which is recycled in D.
  • the process of the present invention allows the discharge, in an integrated process for the production of ter-amyl alkyl ethers, of a paraffinic stream practically without olefins and consequently permits an almost integral use of the olefins available, thus maximizing the production of ter-amyl alkyl ether. It also provides a reduction in the concentration of the paraffins in the cycle and consequently reduces investments and energy consumption.
  • a stream of refinery C 5 hydrocarbon (1) having a stream rate of 17.29 kg/hr combined with the recycled stream (11) having a stream rate of 20.83 kg/hr is fed to a TAME production reactor.
  • TAME (12) A production of TAME (12) is obtained of 8.51 kg/hr equal to a conversion of the reactive isoamylenes of 96%.
  • 31.5 kg/hr of residual C 5 fraction containing about 71% by weight of aliphatic hydrocarbons is discharged from the synthesis reactor, through (3). About 40% of this fraction is by-passed (5) whereas the remaining portion (4) is sent to the molecular sieve separation section operating at 130° C. and 4 bars of pressure. About 30 l of zeolite X is used as adsorbent in the form of extruded pellets of 1/16" whereas n-hexane in the vapour phase (about 4 kg/hr) is used as desorbent of the adsorbed olefins.
  • a stream (6) is discharged, basically consisting of 8.57 kg/hr of aliphatic hydrocarbons with an amount of paraffins of about 95%.
  • the content of paraffinic hydrocarbons in the stream (7) is reduced to about 52% by weight, after separation by distillation of the desorbent and in the stream (8), which joins (7) and (5), the content is 62.4%.
  • the stream (8) is fed to the isomerization section C in which the conversion takes place of the n-pentenes to isoamylenes and other by-products generally belonging to the categories C 4- and C 6+ . These by-products are eliminated (streams 9 and 10) and the resulting fraction (8) is recycled to the TAME synthesis section.
  • the refinery C 5 hydrocarbon stream (1) having a stream rate of 17.29 kg/hr combined with the recycled stream (11) having a stream rate of about 15.52 kg/hr is fed to a TAME production reactor.
  • the stream (3) is fed to the isomerization unit C in which the conversion takes place of the n-pentenes to isoamylenes and other by-products generally belonging to the categories C 4 - and C 6 + . These by-products are eliminated with streams (4) and (5). About 20% is by-passed (7) from the outlet stream (6), containing 69% of paraffinic hydrocarbons, whereas the remaining portion (8) is sent to the adsorption section operating at 130° C. and a pressure of 4 bars.
  • zeolite X is used as adsorbent, in the form of extruded pellets of 1/16" whereas n-hexane in the vapour phase (about 4 kg/hr) is used as desorbent of the adsorbed olefins.
  • a stream (10) is discharged basically consisting of 8.29 kg/hr of aliphatic hydrocarbons with a paraffins content of about 95%.
  • stream (9) the content of paraffinic hydrocarbons is reduced to 48, 9% by weight, after separation by distillation of the desorbent and in stream (11), which joins (7) and (9), the content is 55%.
  • Samples of type-Y zeolite in the form of pellets of 1/16" are heated in a muffle at 400° C. for 5 hours in a nitrogen stream.
  • vapour stream of n-hexane is passed into the tube for about 1000 seconds to saturate the active sites of the zeolite.
  • a C 5 stream, in the vapour phase, is then passed with a stream rate of 0.27 cc/min.
  • composition of the C 5 stream is the following:
  • the C 5 stream is fed to the column for a period of about 1100 seconds.
  • the stream is then stopped and a stream of n-hexane in the vapour phase is then fed with a stream rate of about 0.36 g/min for about 1800 seconds.
  • the discharge effluent leaving the system is condensed in a glass exchanger.
  • the mixture recovered consists of the sum of the adsorbed quantities of C 5 stream and the quantities contained in the volume of the system not occupied by the zeolite.
  • composition of the C 5 mixture recovered at the outlet of the column is the following:
  • the selectivity of the S i system refers to the ratio: ##EQU2## wherein: A and R are, respectively, the molar fractions of the vapour fed and the recovered product;
  • i and o are, respectively, the general component and reference component (n-pentane).

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  • Chemical & Material Sciences (AREA)
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  • Engineering & Computer Science (AREA)
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US08/546,989 1994-12-21 1995-10-23 Integrated process for the production of ter-amyl alkyl ethers Expired - Fee Related US5672771A (en)

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ITMI942589A IT1271313B (it) 1994-12-21 1994-12-21 Processo integrato per la produzione di eteri alchilici ter-amilici
ITMI94A2589 1994-12-21

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EP (1) EP0718269A1 (fi)
AR (1) AR000692A1 (fi)
CA (1) CA2164783A1 (fi)
FI (1) FI956100A (fi)
HU (1) HU214949B (fi)
IT (1) IT1271313B (fi)
NO (1) NO955198L (fi)
RU (1) RU2124494C1 (fi)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6156947A (en) * 1998-06-22 2000-12-05 Uop Llc Process for the production of butene-1 from a mixture of C4 olefins

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA201808597B (en) 2018-02-14 2019-08-28 Indian Oil Corp Ltd Process for etherification of mixed olefinic light naphtha and simultaneous reduction of methanol in the product

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5254748A (en) * 1990-09-04 1993-10-19 Phillips Petroleum Company Methyl-tertiary ether production
US5300696A (en) * 1992-12-29 1994-04-05 Uop C4 rejection for etherification and isomerization process
EP0667329A1 (en) * 1994-02-11 1995-08-16 ENICHEM S.p.A. Integrated process for the simultaneous production of alkyl tert-butyl ethers and 1-butene

Family Cites Families (10)

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Publication number Priority date Publication date Assignee Title
IT1001614B (it) 1973-10-31 1976-04-30 Snam Progetti Procedimento per preparare materia li aventi proprieta meccaniche e termiche migliorate e materiali ottenuti
IT1012686B (it) 1974-05-21 1977-03-10 Snam Progetti Procedimento per la preparazione di eteri ter alchilici
IT1017878B (it) 1974-08-02 1977-08-10 Snam Progetti Processo per la isomerizzazione di alcheni
AR204423A1 (es) 1974-09-19 1976-02-06 Snam Progetti Procedimiento para preparar alumina con propiedades mecanicas mejoradas y alumina asi obtenida
IT1137527B (it) 1981-04-10 1986-09-10 Anic Spa Procedimento per la preparazione di eteri alchilici terziari
IT1243773B (it) 1990-08-01 1994-06-28 Snam Progetti Procedimento per la preparazione di eteri alchilici terziari ed apparecchiatura di distillazione reattiva
CA2043815C (en) * 1990-09-04 1997-04-01 Harvey D. Hensley Methyl-tertiary ether production
GB9103989D0 (en) 1991-02-26 1991-04-10 Shell Int Research Process for the conversion of a feedstock comprising linear olefins
SG67315A1 (en) 1991-06-05 1999-09-21 Lyondell Petrochem Process for isomerizing linear olefins to isoolefins
US5420360A (en) * 1993-08-27 1995-05-30 Mobil Oil Corporation Process for the conversion of C5 linear olefins to tertiary alkyl ethers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5254748A (en) * 1990-09-04 1993-10-19 Phillips Petroleum Company Methyl-tertiary ether production
US5300696A (en) * 1992-12-29 1994-04-05 Uop C4 rejection for etherification and isomerization process
EP0667329A1 (en) * 1994-02-11 1995-08-16 ENICHEM S.p.A. Integrated process for the simultaneous production of alkyl tert-butyl ethers and 1-butene

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6156947A (en) * 1998-06-22 2000-12-05 Uop Llc Process for the production of butene-1 from a mixture of C4 olefins

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FI956100A0 (fi) 1995-12-19
AR000692A1 (es) 1997-08-06
NO955198L (no) 1996-06-24
ITMI942589A0 (it) 1994-12-21
FI956100A (fi) 1996-06-22
HU9503635D0 (en) 1996-05-28
HUT73553A (en) 1996-08-28
ITMI942589A1 (it) 1996-06-21
NO955198D0 (no) 1995-12-20
HU214949B (hu) 1998-08-28
IT1271313B (it) 1997-05-27
CA2164783A1 (en) 1996-06-13
RU2124494C1 (ru) 1999-01-10
EP0718269A1 (en) 1996-06-26

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